CN108303756A - Laser projection module, depth camera and electronic device - Google Patents

Abstract

The invention discloses a laser projection module, a depth camera and an electronic device. The laser projection module comprises a light source, a collimation element and a diffraction optical element. The collimating element includes a plurality of lenses disposed on a light emitting path of the light source. The plurality of lenses includes at least one first type lens and at least one second type lens. The first type of lens includes a transparent substrate including opposing upper and lower surfaces. The first type lens further includes an upper sub-lens formed on the upper surface and a lower sub-lens formed on the lower surface, the upper sub-lens corresponding to the lower sub-lens. The second lens is made of plastic. In the laser projection module, the depth camera and the electronic device, the first lens is manufactured by forming the upper sub-lens and the lower sub-lens on the transparent substrate, so that the problem that the temperature drift phenomenon of the lenses is generated when the environmental temperature changes is solved; the second lens is made of plastic materials, so that the cost is low and the mass production is convenient.

Description

Laser projection module, depth camera and electronics

technical field

The invention relates to the field of imaging technology, in particular to a laser projection module, a depth camera and an electronic device.

Background technique

The laser projection module consists of a light source, a collimator and a diffractive optical element (DOE). The collimation element generally includes a lens structure. When the ambient temperature changes, the lens will have a temperature drift phenomenon. When the temperature drift is large, the focus of the lens will even change, which will affect the laser projected by the laser projection module into the target space. Pattern precision.

Contents of the invention

Embodiments of the present invention provide a laser projection module, a depth camera, and an electronic device.

The laser projection module according to the embodiment of the present invention includes:

a light source for emitting laser light;

A collimation element, the collimation element is used to collimate the laser light, the collimation element includes a plurality of lenses, the plurality of lenses are arranged on the light emitting light path of the light source, and the plurality of lenses include at least one A first type of lens and at least one second type of lens, the first type of lens includes a transparent substrate, the transparent substrate includes an upper surface and a lower surface opposite to each other, and the first type of lens also includes a lens formed on the upper surface An upper sub-lens and a lower sub-lens formed on the lower surface, the upper sub-lens corresponds to the lower sub-lens, and the second type of lens is made of plastic material; and

A diffractive optical element, the diffractive optical element is used to diffract the laser collimated by the collimating element to form a laser pattern.

In some embodiments, the plurality of lenses are coaxially and sequentially arranged on the light-emitting optical path of the light source.

In some embodiments, the multiple lenses include a first lens, a second lens, and a third lens, the first lens includes a first light incident surface and a first light exit surface opposite to each other, and the second lens The lens includes a second light incident surface and a second light exit surface opposite to each other, the third lens includes a third light incident surface and a third light exit surface opposite to each other, the third light incident surface is concave, and the third light incident surface is concave. The light emitting surface is convex.

In some embodiments, the first light incident surface is convex, the first light exit surface is concave, the second light incident surface is concave, and the second light exit surface is concave.

In some embodiments, the plurality of lenses includes a first lens, a second lens, and a third lens,

The first lens is the first type of lens, the second lens and the third lens are the second type of lenses; or

The second lens is the first type lens, and the first lens and the third lens are the second type lenses; or

The third lens is the first type lens, and the first lens and the second lens are the second type lenses; or

The first lens and the second lens are lenses of the first type, and the third lens is a lens of the second type; or

The second lens and the third lens are lenses of the first type, and the first lens is a lens of the second type; or

The first lens and the third lens are the first type of lens, and the second lens is the second type of lens.

In some embodiments, the plurality of lenses includes four lenses,

Two of said lenses are lenses of said first type and two of said lenses are lenses of said second type; or

One of the lenses is the first type of lens, and the other three of the lenses are the second type of lenses; or

Three of the lenses are the first-type lenses, and the other one is the second-type lenses.

In some embodiments, the plurality of lenses are sequentially arranged on the light-emitting optical path of the light source, and the optical axis of at least one of the lenses is shifted relative to the optical axes of the other lenses.

In some embodiments, optical centers of at least two of the lenses are located on the same plane perpendicular to a first direction, and the first direction is a direction from the light source to the diffractive optical element.

In some embodiments, the optical axis of at least one of said lenses is parallel to the optical axes of other said lenses.

In some embodiments, the light source is a vertical cavity surface emitting laser; or the light source is an edge emitting laser.

In some embodiments, the light source is an edge-emitting laser, and the light source includes a light emitting surface facing the collimating element.

The depth camera according to the embodiment of the present invention includes:

The laser projection module described in any one of the above-mentioned embodiments;

an image collector, the image collector is used to collect the laser pattern projected into the target space after passing through the diffractive optical element; and

A processor connected to the laser projection module and the image collector respectively, the processor is used to process the laser pattern to obtain a depth image.

An electronic device according to an embodiment of the present invention includes:

casing; and

The depth camera described in any one of the above embodiments, the depth camera is arranged in the casing and exposed from the casing to acquire a depth image.

In the laser projection module, depth camera, and electronic device in the embodiments of the present invention, the first type of lens is made by forming upper and lower sub-lenses on a transparent substrate, which solves the problem of temperature drift of the lens when the ambient temperature changes Problem; the second type of lens is made of plastic material, which is low in cost and easy for mass production.

Additional aspects and advantages of embodiments of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and understandable from the description of the embodiments in conjunction with the following drawings, wherein:

Fig. 1 is a schematic structural diagram of a laser projection module in some embodiments of the present invention;

2 to 4 are partial structural schematic diagrams of laser projection modules in some embodiments of the present invention;

5 to 16 are partial structural schematic diagrams of the collimation elements of the laser projection module in some embodiments of the present invention;

Fig. 17 is a schematic structural diagram of a depth camera in some embodiments of the present invention;

Fig. 18 is a schematic structural diagram of an electronic device according to some embodiments of the present invention;

Description of main components and symbols:

Laser projection module 100, substrate assembly 10, substrate 11, heat dissipation hole 111, circuit board 12, via hole 121, lens barrel 20, storage cavity 21, top 22, bottom 23, through hole 24, carrying platform 25, first section Structure 26, first stage structure 27, protective cover 30, conflicting surface 31, light transmission hole 32, light source 40, light emitting surface 41, side surface 42, collimating element 50, first type lens 50a, transparent substrate 501, upper surface 5011 , the lower surface 5012, the upper sub-lens 502, the lower sub-lens 503, the second type lens 50b, the first lens 51, the first light incident surface 511, the first light exit surface 512, the second lens 52, the second light incident surface 521, Second light exit surface 522, third lens 53, third light incident surface 531, third light exit surface 532, fourth lens 54, fifth lens 55, sixth lens 56, diffractive optical element 60, diffractive exit surface 61, diffractive Incident surface 62 , sealant 70 , support block 80 , depth camera 400 , projection window 401 , collection window 402 , image collector 200 , processor 300 , electronic device 1000 , and housing 500 .

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, are only for explaining the embodiments of the present invention, and should not be construed as limiting the embodiments of the present invention.

In describing the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front ", "Back", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", etc. The orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiment of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, use a specific configuration and operation, and therefore should not be construed as limiting the embodiments of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be interpreted as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of said features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

In the description of the embodiments of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or It is a detachable connection, or an integral connection; it can be mechanically connected, it can be electrically connected, or it can communicate with each other; it can be directly connected or indirectly connected through an intermediary, and it can be internal communication between two components or two components interaction relationship. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present invention according to specific situations.

The following disclosure provides many different embodiments or examples for implementing different structures of embodiments of the present invention. In order to simplify the disclosure of the embodiments of the present invention, components and arrangements of specific examples are described below. Of course, they are only examples and are not intended to limit the invention. Furthermore, embodiments of the present invention may repeat reference numerals and/or reference letters in different instances, such repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. . In addition, embodiments of the present invention provide examples of various specific processes and materials, but one of ordinary skill in the art may recognize the use of other processes and/or the use of other materials.

Referring to FIG. 1 , a laser projection module 100 according to an embodiment of the present invention includes a substrate assembly 10 , a lens barrel 20 , a protective cover 30 , a light source 40 , a collimating element 50 , and a diffractive optical element 60 .

The substrate assembly 10 includes a substrate 11 and a circuit board 12 carried on the substrate 11 . The material of the substrate 11 can be plastic, for example, polyethylene terephthalate (Polyethylene Glycol Terephthalate, PET), polymethyl methacrylate (Polymethyl Methacrylate, PMMA), polycarbonate (Polycarbonate, PC), poly Any one or more of imides (Polyimide, PI). In this way, the substrate 11 is light in weight and has sufficient supporting strength. The circuit board 12 can be a rigid board, a flexible board or a combination of rigid and flexible boards. A via hole 121 is defined on the circuit board 12 . The light source 40 is fixed on the substrate 11 through the via hole 121 and is electrically connected to the circuit board 12 . Heat dissipation holes 111 may be provided on the substrate 11 through which the heat generated by the light source 40 or the circuit board 12 may be dissipated. The heat dissipation holes 111 may also be filled with thermal conductive glue to further improve the heat dissipation performance of the substrate assembly 10 .

The lens barrel 20 is disposed on the substrate assembly 10 and forms a receiving cavity 21 together with the substrate assembly 10 . The light source 40 , the collimating element 50 , and the diffractive optical element 60 are all accommodated in the housing cavity 21 . The collimating element 50 and the diffractive optical element 60 are sequentially arranged on the light emitting light path of the light source 40 . The lens barrel 20 includes a top 22 and a bottom 23 opposite to each other. The lens barrel 20 is formed with a through hole 24 passing through the top 22 and the bottom 23 . The bottom 23 is carried on the substrate assembly 10 , specifically, it can be fixed on the circuit board 12 by glue. An annular bearing platform 25 extends from the inner wall of the lens barrel 20 toward the center of the through hole 24 , and the diffractive optical element 60 is supported on the bearing platform 25 .

The protective cover 30 is disposed on the top 22 , and the protective cover 30 includes a resisting surface 31 located in the receiving cavity 21 and opposite to the substrate 11 . The protective cover 30 and the carrying platform 25 resist the diffractive optical element 60 from opposite sides of the diffractive optical element 60 respectively. The conflict surface 31 is a surface of the protective cover 30 that conflicts with the diffractive optical element 60 . The laser projection module 100 utilizes the protective cover 30 to contact the diffractive optical element 60 so that the diffractive optical element 60 is accommodated in the housing cavity 21 and prevents the diffractive optical element 60 from falling off along the light emitting direction.

In some embodiments, the protective cover 30 can be made of metal materials, such as nano-silver wires, metal silver wires, copper sheets, and the like. The protective cover 30 defines a light-transmitting hole 32 . The light transmission hole 32 is aligned with the through hole 24 . The light transmission hole 32 is used to emit the laser pattern projected by the diffractive optical element 60 . The aperture size of the light-transmitting hole 32 is smaller than at least one of the width or the length of the diffractive optical element 60 to confine the diffractive optical element 60 in the receiving cavity 21 .

In some embodiments, the protective cover 30 can be made of light-transmitting materials, such as glass, polymethyl methacrylate (Polymethyl Methacrylate, PMMA), polycarbonate (Polycarbonate, PC), polyimide (Polyimide, PI )Wait. Since light-transmitting materials such as glass, PMMA, PC, and PI all have excellent light-transmitting properties, the protective cover 30 does not need to have a light-transmitting hole 32 . In this way, the protective cover 30 can prevent the diffractive optical element 60 from falling off, and prevent the diffractive optical element 60 from being exposed outside the lens barrel 20 , thereby protecting the diffractive optical element 60 from water and dust.

The light source 40 is used to emit laser light. The light source 40 may be a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting Laser, VCSEL) or an edge emitting laser (edge-emitting laser, EEL). In the embodiment shown in FIG. 1 , the light source 40 is an edge emitting laser, specifically, the light source 40 may be a distributed feedback laser (Distributed Feedback Laser, DFB). The light source 40 is used for emitting laser light into the storage cavity 21 . Please refer to FIG. 2 , the light source 40 is columnar as a whole, and one end surface of the light source 40 away from the substrate assembly 10 forms a light-emitting surface 41 . The collimating optical axis is vertical, and the collimating optical axis passes through the center of the light emitting surface 51 . The light source 40 is fixed on the substrate assembly 10 , specifically, the light source 40 can be bonded to the substrate assembly 10 through the sealant 70 , for example, the side of the light source 40 opposite to the light emitting surface 41 is bonded to the substrate assembly 10 . Please refer to FIG. 1 and FIG. 3, the side 42 of the light source 40 can also be bonded to the substrate assembly 10, and the sealing glue 70 can wrap the surrounding side 42, or only one surface of the side 42 can be bonded to the substrate assembly 10 or the substrate assembly 10. Some surfaces are connected to the substrate assembly 10 . At this time, the sealing glue 70 can be a heat-conducting glue, so as to conduct the heat generated by the light source 40 to the substrate assembly 10 .

The light source 40 of the above-mentioned laser projection module 100 adopts an edge-emitting laser. On the one hand, the temperature drift of the edge-emitting laser is smaller than that of the VCSEL array; , the cost of the light source 40 of the laser projection module 100 is low.

When the laser light of the distributed feedback laser is propagating, the power gain is obtained through the feedback of the grating structure. To increase the power of the distributed feedback laser, it is necessary to increase the injection current and/or increase the length of the distributed feedback laser, because increasing the injection current will increase the power consumption of the distributed feedback laser and cause serious heating problems, so , in order to ensure that the distributed feedback laser can work normally, it is necessary to increase the length of the distributed feedback laser, resulting in the distributed feedback laser generally having a slender strip structure. When the light-emitting surface 41 of the edge-emitting laser faces the collimation element 50, the edge-emitting laser is placed vertically. Since the edge-emitting laser is in a slender structure, the edge-emitting laser is prone to accidents such as falling, shifting, or shaking. Therefore, by setting The sealant 70 can fix the side-emitting laser to prevent accidents such as dropping, displacement or shaking of the side-emitting laser.

In some implementations, the light source 40 can also be fixed on the substrate assembly 10 in a fixing manner as shown in FIG. 4 . Specifically, the laser projection module 100 includes a plurality of support blocks 80, the support blocks 80 can be fixed on the substrate assembly 10, and the plurality of support blocks 80 jointly surround the light source 40, and the light source 40 can be directly installed on the plurality of support blocks during installation. Between 80. In one example, a plurality of supporting blocks 80 jointly clamp the light source 40 to further prevent the light source 40 from shaking.

Please refer to FIG. 1 again, the collimating element 50 is used to collimate the laser light emitted by the light source 40 . The collimating element 50 is fixed on the lens barrel 20 , and the carrying platform 25 is located between the collimating element 50 and the diffractive optical element 60 . The collimating element 50 includes a plurality of lenses, and the plurality of lenses are arranged on the light emitting light path of the light source 40 . The plurality of lenses includes at least one first type lens 50a and at least one second type lens 50b. The first type of lens 50 a includes a transparent substrate 501 . The transparent substrate 501 includes an upper surface 5011 and a lower surface 5012 opposite to each other. The first type of lens 50 a further includes an upper sub-lens 502 formed on the upper surface 5011 and a lower sub-lens 503 formed on the lower surface 5012 , the upper sub-lens 202 corresponds to the lower sub-lens 503 . The second type lens 50b is made of plastic material. Since the first type of lens 50a is made by forming an upper sub-lens 502 and a lower sub-lens 503 on a transparent substrate 501, the problem of temperature drift of the lens when the ambient temperature changes is solved; while the second type of lens 50b is made of plastic material, low cost and convenient for mass production.

Specifically, the first type of lens 50a can be manufactured by a WLO (Wafer Level Optics) process. The transparent substrate 501 can be a glass substrate. Firstly, UV glue is coated on the upper surface 5011 and the lower surface 5012 of the transparent substrate 501, and then the upper sub-lens 502 and the lower sub-lens 503 are formed by photolithography. The upper sub-lens 502 can be a convex lens, and the lower sub-lens 503 is also a convex lens (as shown in Figure 1); perhaps, the upper sub-lens 502 is a concave lens, and the lower sub-lens 503 is also a concave lens; perhaps, the upper sub-lens 502 is a convex lens, and the lower sub-lens 503 is a concave lens; or, the upper sub-lens 502 is a concave lens, and the lower sub-lens 503 is a convex lens. The first type of lens 50a made by the WLO process can solve the thermal deformation of the collimation element 50, which makes the optical effect worse (for example, the speckle becomes larger), and affects the ability of the laser projection module 100 to project the laser pattern into the target space. A question of precision.

In some implementations, the collimating element 50 may include a plurality of lenses, and the plurality of lenses are arranged coaxially and sequentially on the light-emitting optical path of the light source 40 . The surface type of each lens can be any one of aspherical surface, spherical surface, Fresnel surface and binary optical surface.

For example: please refer to FIG. 1 and FIG. 5 together, the plurality of lenses may include a first lens 51 and a second lens 52 . The first lens 51 and the second lens 52 are arranged coaxially and sequentially on the light emitting light path of the light source 40 . The first lens 51 includes a first light incident surface 511 and a first light output surface 512 opposite to each other. The first light incident surface 511 is the surface of the first lens 51 close to the light source 40 , and the first light exit surface 512 is the surface of the first lens 51 close to the diffractive optical element 60 . The second lens 52 includes a second light incident surface 521 and a second light output surface 522 opposite to each other. The second light incident surface 521 is the surface of the second lens 52 close to the light source 40 , and the second light exit surface 522 is the surface of the second lens 52 close to the diffractive optical element 60 . The apex of the first light-emitting surface 512 is in contact with the apex of the second light-incident surface 521 , the first light-incident surface 511 is a concave surface, and the second light-emitting surface 522 is a convex surface. The diaphragm is disposed on the second light incident surface 521 for limiting the light beam. Further, both the first light-emitting surface 512 and the second light-incident surface 521 may be convex. In this way, it is convenient for the apex of the first light-emitting surface 512 to collide with the apex of the second light-incident surface 521 . The curvature radius of the first light emitting surface 512 is smaller than the curvature of the second light incident surface 521 .

In the collimating element 50 shown in FIG. 5 , the first lens 51 is a first-type lens 50a (it should be pointed out that the incident surface of the first-type lens 50a is the surface of the lower sub-lens 503 close to the light source 40, the first The light-emitting surface of the class lens 50a is the surface of the upper sub-lens 502 close to the diffractive optical element 60, the same below), and the second lens 52 is the second class lens 50b; certainly, in other examples, the second lens 52 can be the first The first lens 51 of the type lens 50a may be the second type lens 50b.

Please refer to FIG. 1 and FIG. 6 together, the plurality of lenses may further include a first lens 51 , a second lens 52 , and a third lens 53 . The first lens 51 , the second lens 52 , and the third lens 53 are arranged coaxially and sequentially on the light emitting light path of the light source 40 . The first lens 51 includes a first light incident surface 511 and a first light output surface 512 opposite to each other. The first light incident surface 511 is the surface of the first lens 51 close to the light source 40 , and the first light exit surface 512 is the surface of the first lens 51 close to the diffractive optical element 60 . The second lens 52 includes a second light incident surface 521 and a second light output surface 522 opposite to each other. The second light incident surface 521 is the surface of the second lens 52 close to the light source 40 , and the second light exit surface 522 is the surface of the second lens 52 close to the diffractive optical element 60 . The third lens 53 includes a third light incident surface 531 and a third light exit surface 532 opposite to each other. The third light incident surface 531 is the surface of the third lens 53 close to the light source 40 , and the third light exit surface 532 is the surface of the third lens 53 close to the diffractive optical element 60 . The third light incident surface 531 is concave, and the third light exit surface 532 is convex. The diaphragm is disposed on the third light emitting surface 532 for limiting the light beam. Further, the first light incident surface 511 may be convex, the first light exit surface 512 is concave, the second light incident surface 521 is concave, and the second light exit surface 522 is concave.

In the collimating element 50 shown in Figure 6, the first lens 51 and the second lens 52 are the first type lens 50a, and the third lens 53 is the second type lens 50b; of course, in other examples, the first lens 51 Can be the first type lens 50a, the second lens 52 and the third lens 53 can be the second type lens 50b; Or, the second lens 52 is the first type lens 50a, the first lens 51 and the third lens 53 are the second type lens Class lens 50b; Or, the third lens 53 is the first class lens 50a, and the first lens 51 and the second lens 52 are the second class lens 50b; Perhaps, the second lens 52 and the third lens 53 are the first class lens 50a , the first lens 51 is the second type lens 50b; or, the first lens 51 and the third lens 53 are the first type lens 50a, and the second lens 52 is the second type lens 50b.

Please refer to FIG. 1 and FIG. 7 together, the plurality of lenses may further include a first lens 51 , a second lens 52 , a third lens 53 , and a fourth lens 54 . Wherein two lenses are the first type lens 50a, other two lenses are the second type lens 50b, for example, the second lens 52 and the third lens 53 are the first type lens 50a, the first lens 51 and the fourth lens 54 are Second type lens 50b (as shown in Figure 7); Or one of them lens is first type lens 50a, and other three lenses are second type lens 50b, for example, first lens 51 is first type lens 50a, the second Lens 52, the third lens 53, and the fourth lens 54 are the second type lens 50b; or three of them are the first type lens 50a, and the other lens is the second type lens 50b, for example, the first lens 51, the second type lens The second lens 52 and the third lens 53 are the first type lens 50a, and the fourth lens 54 is the second type lens 50b.

Of course, in other examples, the multiple lenses may include more lenses, as long as the multiple lenses include at least one first-type lens 50a and at least one second-type lens 50b.

In some embodiments, collimating element 50 includes a plurality of lenses. A plurality of lenses are sequentially arranged on the light-emitting optical path of the light source 40, and the optical axis of at least one lens is offset relative to the optical axes of other lenses. At this time, the structure of the lens barrel 20 may be one or more segments, and each segment is used to install a corresponding lens.

For example: please refer to FIG. 8 to FIG. 12 together, the collimation element 50 includes a first lens 51 , a second lens 52 and a third lens 53 . The first lens 51 , the second lens 52 and the third lens 53 are sequentially arranged on the light emitting light path of the light source 40 . The optical axis of the second lens 52 deviates with respect to the optical axis of the first lens 51, the optical axis of the first lens 51 coincides with the optical axis of the third lens 53 (as shown in Figure 8), further, the second lens 52 The optical axis of the lens can be parallel to the optical axis of the first lens 51. At this time, the structure of the lens barrel 20 can be a two-stage structure, the first stage structure 26 is used to install the first lens 51 and the second lens 52, and the second stage structure 27 is used to install the third lens 53, the first segment structure 26 is obliquely connected to the second segment structure 27, and the second lens 52 is installed at the junction of the first segment structure 26 and the second segment structure 27, so that multiple The curved structure of the lens is conducive to increasing the optical path, thereby reducing the overall height of the laser projection module 100. The inner walls of the first segment structure 26 and the second segment structure 27 are coated with a reflective coating, and the reflective coating is used for Reflect light so that the light emitted by the light source 40 can sequentially pass through the first light incident surface 511, the first light exit surface 512, the second light incident surface 521, the second light exit surface 522, the third light incident surface 531, and the third light exit surface surface 532; of course, in other embodiments, the first segment structure 26 and the second segment structure 27 can also be reflective elements independent of the lens barrel 20, the reflective elements are arranged on the lens barrel 20, and the reflective elements are prisms or mirrors etc., the reflective element is used to reflect light to change the direction of the optical path; or, the optical axis of the first lens 51 is offset with respect to the optical axis of the second lens 52, and the optical axis of the second lens 52 and the optical axis of the third lens 53 Overlap (as shown in Figure 9), further, the optical axis of the first lens 51 can be parallel with the optical axis of the second lens 52; Or, the optical axis of the third lens 53 deviates with respect to the optical axis of the first lens 51 , the optical axis of the first lens 51 coincides with the optical axis of the second lens 52 (as shown in Figure 10), further, the optical axis of the third lens 53 can be parallel to the optical axis of the first lens 51; or, the second The optical axis of the lens 52 deviates relative to the optical axis of the first lens 51, the optical axis of the third lens 53 deviates relative to the optical axis of the first lens 51, the optical axis of the second lens 52 and the light of the third lens 53 Axis is positioned at the same side (as shown in Figure 11) of the optical axis of the first lens 51, further, the optical axis of the first lens 51 can be parallel with the optical axis of the second lens 52, the optical axis of the first lens 51 is parallel with the optical axis of the second lens 51 The optical axes of the three lenses 53 are parallel, and the optical axis of the second lens 52 is parallel to the optical axis of the third lens 53; or, the optical axis of the second lens 52 deviates relative to the optical axis of the first lens 51, and the third lens 53 The optical axis of the first lens 51 deviates with respect to the optical axis of the first lens 51, the optical axis of the second lens 52 and the optical axis of the third lens 53 are located on the opposite side of the optical axis of the first lens 51 (as shown in Figure 12), further Specifically, the optical axis of the first lens 51 can be parallel to the optical axis of the second lens 52, the optical axis of the first lens 51 can be parallel to the optical axis of the third lens 53, and the optical axis of the second lens 52 can be parallel to the optical axis of the third lens 53. The optical axes are parallel.

Preferably, the optical axis of the second lens 52 is offset relative to the optical axis of the first lens 51, the optical axis of the third lens 53 is offset relative to the optical axis of the first lens 51, and the optical axis of the second lens 52 and The optical axis of the third lens 53 is located on the opposite side of the optical axis of the first lens 51 . In this way, the bent structure of multiple lenses is beneficial to increase the optical path, increase the focal length, and reduce the height of the laser projection module 100 . Of course, the collimating element 50 can also include more lenses. For example, referring to FIG. 13, the collimating element 50 includes a first lens 51, a second lens 52, a third lens 53, a fourth lens 54, and a fifth lens. 55, and the sixth lens 56. The first lens 51 , the second lens 52 , the third lens 53 , the fourth lens 54 , the fifth lens 55 , and the sixth lens 56 are sequentially arranged on the light emitting light path of the light source 40 . The optical axis of the second lens 52 deviates relative to the optical axis of the first lens 51, the optical axis of the third lens 53 deviates relative to the optical axis of the first lens 51, and the optical axis of the second lens 52 and the third lens 53 The optical axis of the first lens 51 is located on the opposite side of the optical axis of the first lens 51, the optical axis of the fourth lens 54 coincides with the optical axis of the second lens 52, the optical axis of the fifth lens 55 coincides with the optical axis of the third lens 53, and the optical axis of the fifth lens 55 coincides with the optical axis of the third lens 53. The optical axis of the six lenses 56 coincides with the optical axis of the first lens 51 .

It should be pointed out that, in the laser projection module 100 shown in FIGS. 9 to 13 , the structure of the lens barrel 20 is the same or similar to that of the lens barrel 20 shown in FIG. The multi-segment structure will not be repeated here.

In some embodiments, the collimating element 50 includes a plurality of lenses, and the optical centers of at least two lenses are located on the same plane perpendicular to the first direction, which is the direction from the light source 40 to the diffractive optical element 60 .

For example: please refer to FIG. 14 to FIG. 16 together, the collimating element 50 includes a first lens 51 , a second lens 52 and a third lens 53 . The optical center of the first lens 51 and the optical center of the second lens 52 are located on the same plane (as shown in Figure 14), and the optical axis of the first lens 51 and the optical axis of the second lens 52 can be positioned at the optical axis of the third lens 53. Or, the optical center of the second lens 52 and the optical center of the third lens 53 are located on the same plane (as shown in Figure 15), the optical axis of the second lens 52 and the optical axis of the third lens 53 can be Or, the optical center of the first lens 51 and the optical center of the third lens 53 are located on the same plane; or, the optical center of the first lens 51, the light of the second lens 52 The optical center and the optical center of the third lens 53 are all located on the same plane (as shown in FIG. 16 ). Further, the optical axis of the first lens 51 can be parallel to the optical axis of the second lens 52, the optical axis of the first lens 51 can be parallel to the optical axis of the third lens 53, and the optical axis of the second lens 52 can be parallel to the optical axis of the third lens 53. The optical axes are parallel.

Please refer to FIG. 1 again, the diffractive optical element 60 is used to diffract the laser collimated by the collimating element 50 to form a laser pattern. The diffractive optical element 60 includes a diffractive exit surface 61 and a diffractive entrance surface 62 opposite to each other. The protective cover 30 can be pasted on the top 22 by glue, the conflicting surface 31 is in conflict with the diffractive exit surface 61, and the diffractive incident surface 62 is in conflict with the carrying platform 25, so that the diffractive optical element 60 will not fall off from the receiving cavity 21 along the light emitting direction. The diffractive optical element 60 can be made of glass, or composite plastic (such as PET).

When assembling the above-mentioned laser projection module 100 , put the collimation element 50 and the substrate assembly 10 with the light source 40 installed into the through hole 24 sequentially along the optical path from the bottom 23 of the lens barrel 20 . The light source 40 can be installed on the substrate assembly 10 first, and then the substrate assembly 10 on which the light source 40 is installed is fixed to the bottom 23 . Put the diffractive optical element 60 into the through hole 24 from the top 22 against the direction of the optical path and place it on the carrying platform 25, then install the protective cover 30, and make the diffractive outgoing surface 61 of the diffractive optical element 60 conflict with the protective cover 30, The diffractive incident surface 62 interferes with the carrying table 25 . The laser projection module 100 has a simple structure and is easy to assemble.

Please refer to FIG. 17 , the depth camera 400 according to the embodiment of the present invention includes the laser projection module 100 , the image collector 200 , and the processor 300 according to any of the above embodiments. The image collector 200 is used to collect the laser pattern projected into the target space after passing through the diffractive optical element 50 . The processor 300 is connected to the laser projection module 100 and the image collector 200 respectively. The processor 300 is used to process the laser pattern to obtain a depth image.

Specifically, the laser projection module 100 projects the laser pattern projected into the target space through the projection window 401 , and the image collector 200 collects the laser pattern modulated by the target object through the collection window 402 . The image collector 200 can be an infrared camera, and the processor 300 uses an image matching algorithm to calculate the deviation value of each pixel point in the laser pattern and the corresponding pixel point in the reference pattern, and then further obtains the depth of the laser pattern according to the deviation value image. Wherein, the image matching algorithm may be a digital image correlation (Digital Image Correlation, DIC) algorithm. Of course, other image matching algorithms can also be used instead of the DIC algorithm.

In the depth camera 400 according to the embodiment of the present invention, the first type of lens 50a is made by forming an upper sub-lens 502 and a lower sub-lens 503 on a transparent substrate 501, which solves the problem of temperature drift of the lens when the ambient temperature changes ; The second type of lens 50b is made of plastic material, which is low in cost and convenient for mass production.

Please refer to FIG. 18 , an electronic device 1000 according to an embodiment of the present invention includes a housing 500 and the depth camera 400 of the above embodiment. The depth camera 400 is disposed inside the housing 500 and exposed from the housing 500 to acquire a depth image. The electronic device 1000 includes, but is not limited to, a mobile phone, a tablet computer, a laptop computer, a smart bracelet, a smart watch, a smart helmet, and smart glasses.

In the electronic device 1000 of the embodiment of the present invention, the first type of lens 50a is manufactured by forming an upper sub-lens 502 and a lower sub-lens 503 on a transparent substrate 501, which solves the problem of temperature drift of the lens when the ambient temperature changes ; The second type of lens 50b is made of plastic material, which is low in cost and convenient for mass production.

In the description of this specification, reference to the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific examples" or "some examples" etc. Specific features, structures, materials, or features described in an embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiment of the present invention has been shown and described above, it can be understood that the above embodiment is exemplary and should not be construed as a limitation of the present invention, and those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (13)

1. A laser projection module, characterized in that it comprises: a light source for emitting laser light; A collimation element, the collimation element is used to collimate the laser light, the collimation element includes a plurality of lenses, the plurality of lenses are arranged on the light emitting light path of the light source, and the plurality of lenses include at least one A first type of lens and at least one second type of lens, the first type of lens includes a transparent substrate, the transparent substrate includes an upper surface and a lower surface opposite to each other, and the first type of lens also includes a lens formed on the upper surface An upper sub-lens and a lower sub-lens formed on the lower surface, the upper sub-lens corresponds to the lower sub-lens, and the second type of lens is made of plastic material; and A diffractive optical element, the diffractive optical element is used to diffract the laser collimated by the collimating element to form a laser pattern. 2 . The laser projection module according to claim 1 , wherein the plurality of lenses are arranged coaxially and sequentially on the light-emitting optical path of the light source. 3 . 3. The laser projection module according to claim 2, wherein the plurality of lenses include a first lens, a second lens, and a third lens, and the first lens includes opposite first incident light The second lens includes a second light incident surface and a second light exit surface opposite to each other, the third lens includes a third light incident surface and a third light exit surface opposite to each other, and the first lens includes a third light incident surface and a third light exit surface opposite to each other. The three light-incoming surfaces are concave, and the third light-emitting surface is convex. 4. The laser projection module according to claim 3, wherein the first light incident surface is convex, the first light exit surface is concave, the second light incident surface is concave, and the first light incident surface is concave. The second light-emitting surface is concave. 5. The laser projection module according to claim 2, wherein the plurality of lenses comprises a first lens, a second lens, and a third lens, The first lens is the first type of lens, the second lens and the third lens are the second type of lenses; or The second lens is the first type lens, and the first lens and the third lens are the second type lenses; or The third lens is the first type lens, and the first lens and the second lens are the second type lenses; or The first lens and the second lens are lenses of the first type, and the third lens is a lens of the second type; or The second lens and the third lens are lenses of the first type, and the first lens is a lens of the second type; or The first lens and the third lens are the first type of lens, and the second lens is the second type of lens. 6. The laser projection module according to claim 2, wherein the plurality of lenses comprises four lenses, two of which are the first-type lenses, and the other two are the first-type lenses. the second type of lens; or one of the lenses is the first type of lens, and the other three lenses are the second type of lens; or three of the lenses are the first type of lens, in addition One said lens is said second type lens. 7. The laser projection module according to claim 1, wherein the plurality of lenses are sequentially arranged on the light-emitting optical path of the light source, and the optical axis of at least one lens is relative to the optical axis of the other lenses. axis offset. 8. The laser projection module according to claim 1, wherein the optical centers of at least two of the lenses are located on the same plane perpendicular to the first direction, the first direction is from the light source to the The orientation of the diffractive optical element described above. 9. The laser projection module according to claim 7 or 8, wherein the optical axis of at least one of the lenses is parallel to the optical axes of the other lenses. 10. The laser projection module according to claim 1, wherein the light source is a vertical cavity surface emitting laser; or the light source is an edge emitting laser. 11 . The laser projection module according to claim 1 , wherein the light source is an edge-emitting laser, the light source includes a light-emitting surface, and the light-emitting surface faces the collimation element. 12. A depth camera, comprising: The laser projection module according to any one of claims 1-11; an image collector, the image collector is used to collect the laser pattern projected into the target space after passing through the diffractive optical element; and A processor connected to the laser projection module and the image collector respectively, the processor is used to process the laser pattern to obtain a depth image. 13. An electronic device, characterized in that it comprises: casing; and The depth camera of claim 12 disposed within and exposed from the housing to acquire a depth image.